alright, swapped my tires to PS2s that I bought a couple of months ago... what a difference does it make on my 18"... The ride is so much smoother. No more of this echoing bump sounds when I drive on road transitions. The low profile RFTs are just a bad idea. I also felt the difference carrying the PS2 and the RE50 RFT. You can definitely tell there is a huge weight difference. I am not going back that's for sure.
2000 Z3 2.8 TiAg (retired)
2002 330i Orient Blue (retired)
2005 330Ci TiAg (retired)
2009 Z4 30i Space Gray (retired)
2011 Z4 35is Space Gray
2011 535i GT xDrive Space Gray